Proposal of a comprehensive definition of modified and other forms of mycotoxins including masked mycotoxins

As the term masked mycotoxins encompasses only conjugated mycotoxins generated by plants and no other possible forms of mycotoxins and their modifications, we hereby propose for all these forms a systematic definition consisting of four hierarchic levels. The highest level differentiates the free and unmodified forms of mycotoxins from those being matrix-associated and from those being modified in their chemical structure. The following lower levels further differentiate, in particular, modified mycotoxins into biologically modified and chemically modified with all variations of metabolites of the former and dividing the latter into thermally formed and non-thermally formed ones. To harmonize future scientific wording and subsequent legislation, we suggest that the term modified mycotoxins should be used in the future and the term masked mycotoxins to be kept for the fraction of biologically modified mycotoxins that were conjugated by plants.